Carbs

I recently purchased a 1995 37' Sea Ray EC with stock Mercury inboards (Gen 5 454's), Weber carbs, & closed cooling. I have never owned a boat with Weber's or closed cooling. It seems to take a very long time to warm up engines. If I untie and take off too soon, the engines sometimes will "stumble" and stall if I don't "nerf" and play with the throttles.
Also , sometimes when I have been running for a while and throttle down, put it in neutral, the engines will not idle below 1,100 RPM's until I play with the throttles.
I am thinking about replacing carbs and wonder if "Demon" would be a good choice. I know they are meant for high performance boats, but it doesn't seem like it would hurt anything except my bank account.
Would I get any benefit ?
Thanks, Tim

 

webbers are good carb's, but maybe they nead some adjustment or cleaning?
Is the ignition correct?
Did you make absolutely shure that the carbs are the problem?
For the heating thing is the thermostat ok?

 

Ok so they stumble a bit 'some times' if you take off too 'early'. Sounds like they are pretty near the mark to me.
Are you talking 2 engines the same here?
-Your throttle cables need adjustment for the slow running speed

 

I'm not sure if replacing the carbs would be the solution. More likely the ones you have aren't adjusted properly for your operating conditions. Did the previous owner of the boat run it mainly at a different altitude or in much warmer or much colder weather than you do? If (s)he did, your carbs might just need cleaning and jet adjustment. As for the 1100rpm idle thing, I suspect the cables and not the carbs are at fault here; check their adjustments and lubricate them.